NEW YORK  Investors have been hoping for months that the stock market will come roaring back.

But a new analysis of legal insider trading shows that corporate executives  the people with the best insight into how their companies are doing  are selling their own stock at an alarmingly bearish rate. Consider:

 Insiders sold $5.2 billion worth of stock in May, compared with $2.9 billion in April, according to the most recent data from Thomson Financial/Lancer Analytics. That's the largest monthly sale of insider stock since August and significantly higher than the monthly average of $3.5 billion.

 The ratio of stock sold by insiders to stock bought jumped in May. For every dollar insiders spent buying, they sold $34.11. That's more than double the figure for April, $15.98, and nearly triple the average ratio of 12-to-1.

 The rate of insider buying fell 15 percent from April to May, from $179.7 million to $152.5 million.

Analysts say the May statistics are significant because corporate insiders tend to have the best idea of how well or poorly their companies are going to perform.

"Right now, maybe executives don't feel there will be a summer rally," says Lon Gerber, director of research for Thomson Financial/Lancer Analytics. "We're at the most bearish point ever."

To bears, the numbers prove what they've been saying all along.

"People don't want to give up on the idea that stocks go up every year," says David Tice, portfolio manager at the Prudent Bear fund.

Tice says many people now are hoping that stocks have hit bottom because lower interest rates are going to help corporate profits.

"But Corporate America realizes that it's not the case, and they're taking money off the table," he says.

And unlike last year, when selling centered on tech companies, analysts point out that executives at companies across all industries are lightening up now.